"There's" with plural referent

[September]

The other day, I had a conversation that went like this:

"Could you sweep?"
-"Someone else is already sweeping."
"There's two brooms."

It "should" be "There are two brooms", but I would never have said that. Perhaps because "there's" is shorter without being as clunky as "there're"? Has anyone else observed this? Do you ever use "there's" when what you're referring to is plural?

[TeneReef]

It's more common than not.

[linguoboy]

Yeah, it's becoming an unanalysable presentational expression, just like French voilà (historically an informal singular imperative--"see [thou] there!"--but now used regardless of audience).

[TeneReef]

Or (a group of ) men in Portuguese saying obrigado (sg) rather than obrigados (pl).

[September]

Great examples! Thanks, guys!

[Osias]

Or (a group of ) men in Portuguese saying obrigado (sg) rather than obrigados (pl).